Multiplex datastore

[bukajsytlos]

Hello, I am trying to figure out a way how to have references across multiple datastores (MultiplexManager).
I found reference to BridgeableTransaction, but it looks kind of cumbersome to use or at least the example in test needs custom datastore and having hardcoded entities/relationships. Is there some more easier way? As far as I understand each entity is bound to datastore, so I would assume it could be default behaviour, elide should know where and how to load relationships? In my case I have two hibernate stores and when I tried to use entity from other datastore, hibernate/spring throws this error

Caused by: org.hibernate.AnnotationException: @OneToOne or @ManyToOne on com.faforever.api.league.domain.LeagueSeasonScore.player references an unknown entity: com.faforever.api.data.domain.Player
    at org.hibernate.cfg.ToOneFkSecondPass.doSecondPass(ToOneFkSecondPass.java:100)
    at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processEndOfQueue(InFlightMetadataCollectorImpl.java:1823)
    at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processFkSecondPassesInOrder(InFlightMetadataCollectorImpl.java:1767)
    at org.hibernate.boot.internal.InFlightMetadataCollectorImpl.processSecondPasses(InFlightMetadataCollectorImpl.java:1655)
    at org.hibernate.boot.model.process.spi.MetadataBuildingProcess.complete(MetadataBuildingProcess.java:295)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.metadata(EntityManagerFactoryBuilderImpl.java:1224)
    at org.hibernate.jpa.boot.internal.EntityManagerFactoryBuilderImpl.build(EntityManagerFactoryBuilderImpl.java:1255)
    at org.springframework.orm.jpa.vendor.SpringHibernateJpaPersistenceProvider.createContainerEntityManagerFactory(SpringHibernateJpaPersistenceProvider.java:58)

so not sure if this even possible without some workaround? Thanks

[aklish]

If you are going to bridge between stores, you will want to decorate the relationships with Elide's relationship annotations instead of JPA so JPA doesn't try to search for an entity it doesn't manage:

https://github.com/yahoo/elide/blob/master/elide-core/src/main/java/com/yahoo/elide/annotation/ToMany.java
and
https://github.com/yahoo/elide/blob/master/elide-core/src/main/java/com/yahoo/elide/annotation/ToOne.java

Some logic still needs to hydrate those relationships (either done in the store during load or maybe through a life cycle hook on read).

If you are just trying to bridge between two stores (two different JPA entity managers), it seems possible to generalize this somehow although Elide doesn't have any logic for this use case.

We have one production instance that bridges between Hbase and MySQL. However, that required custom logic.

[bukajsytlos]

thanks